Australia hints of scaling back MH370 hunt

"I do reassure the families of our hope and expectation that the ongoing search will succeed," Abbott told parliament in Canberra. "My pledge is that we are taking every reasonable step to bring your uncertainty to an end."

"I can't promise that the search will go on at this intensity forever but we will continue our very best efforts to resolve this mystery and provide some answers."

Australia is leading the hunt in the Indian Ocean some 1,000 miles off its west coast, with four ships using sophisticated sonar systems to scour a huge underwater area.

The vessels are focusing on a 23,000 square mile priority zone, with the search scheduled to end in May. More than 40 percent of the ocean floor has been explored to date.

The intensive search — jointly funded by Australia and Malaysia with a budget of $93 million — has so far only turned up little although it has benefitted scientists.

The ships, Fugro Supporter, Fugro Equator, Fugro Discovery and GO Phoenix, are working in one of the world's most isolated locations in treacherous conditions similar to the "Roaring Forties" north of Antarctica, which are notorious among mariners for its hostile seas.

Weather conditions in the remote region are expected to worsen after May.

If the plane isn't found by May, one option is to expand the hunt beyond the current search zone into a wider area surrounding it, Australian Transport Minister Warren Truss said. The larger area is 425,000 square miles, or nearly 20 times the size of the current search zone, which itself is expected to take more than seven months to cover. 

The plane, of course, could be found at any moment. But officials must prepare for the possibility that it won't be.

Ministers from Australia, China and Malaysia will meet next month to decide whether and how to fund another phase of the search. But if the search continues to come up empty, funds and options will one day dry up.

"If it's a search that has no hope, then there has to be a line drawn in the sand where ultimately somebody's going to have to make that decision," says U.K.-based airline security analyst Chris Yates. "There's going to have to be some soul-searching."

The agency coordinating the search, the Australian Transport Safety Bureau, has previously said a decision on continuing after the current hunt was completed was up to the Australian and Malaysian governments.

Abbott said the plane's disappearance "demonstrated a fundamental gap in tracking long-haul flights, particularly over the oceans."

Australia, Malaysia and Indonesia plan to hold trials of a "world first" system that increases the tracking of aircraft over remote oceans to a minimum rate of every 15 minutes from current intervals of 30 to 40 minutes.

Agence-France Presse